ALERT SERVICE BULLETIN AS350 

Approved under EASA DOA No. 21J.056. 29.00.13 Page 1/10

 2010.07.26 This document is available on the internet: www.eurocopter.com/techpub 

 EUROCOPTER

DIRECTION TECHNIQUE SUPPORT

13725 MARIGNANE CEDEX FRANCE CIVIL VERSION(S): B,BA,BB,D,B1, B2,B3

 MILITARY VERSION(S): L1

 ALERT SERVICE BULLETIN 

No. 29.00.13 

SUBJECT: HYDRAULIC POWER 

Protection of the forward servo-control hoses

Corresponds to modification 074238 

REVISION No. DATE OF APPROVAL DATE OF ISSUE 

 

Revision 0 On: July 23, 2010 2010.07.26 

 

 

 

 
 ALERT SERVICE BULLETIN AS350 

Approved under EASA DOA No. 21J.056. 29.00.13 Page 2/10

 2010.07.26

1. PLANNING INFORMATION 

1.A. EFFECTIVITY 

1.A.1. Helicopters/installed equipment 

Helicopters with a single hydraulic power system which are not modified by modification 074238 and which 

are equipped with both the forward (pitch) servo-control hydraulic hoses referenced below: 

- P/N 704A34-412-033 or MP/N 675-102-05-01, 

- P/N 704A34-412-035 or MP/N 675-102-06-01. 

NOTE

Refer to Figure 1 for an illustration of hoses (a) and (b) 

concerned by this ALERT SERVICE BULLETIN. 

1.A.2. Non-installed equipment 

Not applicable. 

1.B. ASSOCIATED REQUIREMENTS 

Not applicable. 

1.C. REASON 

To protect the forward servo-control hydraulic hoses against possible spattering with molten metal due to the 

deterioration of the electric motor located nearby. 

This ALERT SERVICE BULLETIN will form the subject of an EASA Airworthiness Directive. 

1.D. DESCRIPTION 

During a load carrying mission, the pilot smelt burning in the cabin and noticed that the engine oil 

temperature had increased to 110°C. He then noted a loss of hydraulic assistance which compelled him to 

make an emergency landing. 

Once the helicopter was on the ground, the pilot extinguished the fire which was located on the oil cooler. 

The examinations carried out on the helicopter have shown that the fan electric motor was highly 

deteriorated. A short circuit on the power supply may have spattered molten metal which damaged the 

surrounding hydraulic pipes. The fire was caused by the hydraulic leak due to this damage, associated with 

the electric arcing. 

Modification 074238 has been introduced in order to protect the hydraulic pipes. This modification consists in 

installing two siliconed glass wool sleeves on both hoses of the forward main rotor servo-control, specified in 

paragraph 1.A.1. 
 ALERT SERVICE BULLETIN AS350 

Approved under EASA DOA No. 21J.056. 29.00.13 Page 3/10

 2010.07.26

1.E. COMPLIANCE 

EUROCOPTER renders compliance with this ALERT SERVICE BULLETIN mandatory. 

1.E.1. Compliance at the works 

1.E.1.a. Helicopters/installed equipment: Comply with paragraph 2. before delivery.

1.E.1.b. Non-installed equipment: Not applicable.

1.E.2. Compliance in service: By the operator

1.E.2.a. Helicopters/installed equipment 

Comply with paragraph 2. within 6 months following receipt of this ALERT SERVICE BULLETIN, issued 

on the date indicated at the foot of the page. 

1.E.2.b. Non-installed equipment: Not applicable.

1.F. APPROVAL 

1.F.1. Approval of the Service Bulletin 

The technical information contained in this ALERT SERVICE BULLETIN Revision 0 was approved 

on July 23, 2010 under the authority of EASA Design Organization Approval No. 21J.056 for helicopters of 

civil versions subject to an Airworthiness Certificate. 

The technical information contained in this ALERT SERVICE BULLETIN Revision 0 was approved 

on July 23, 2010 under Registered Letter Ref. No. 346621 DGA/DT/CEP/ASA for French Government 

helicopters. 

The technical information contained in this ALERT SERVICE BULLETIN Revision 0 was approved 

on July 23, 2010 by the EUROCOPTER Airworthiness Department for export military versions 

1.F.2. Approval of the modifications 

The information or instructions relate to modification 074238 which was approved on 22/07/2010 by EASA 

for civil version helicopters subject to an Airworthiness Certificate. 

1.G. MANPOWER 

Qualification: 1 mechanic. 

Times for the operations: 1 hour. 
 ALERT SERVICE BULLETIN AS350 

Approved under EASA DOA No. 21J.056. 29.00.13 Page 4/10

 2010.07.26

1.H. WEIGHT AND BALANCE 

Not applicable. 

1.I. EFFECT ON ELECTRICAL LOADS 

Not applicable. 

1.J. SOFTWARE MODIFICATION EMBODIMENT RECORD 

Not applicable. 

1.K. REFERENCES 

Maintenance Manual (MET): 

- Work Card 29.00.00.301, 

- Work Card 29.10.10.404. 

Standard Practices Manual (MTC): 

- Work Card 20.07.03.408, 

- Work Card 20.02.01.411. 

1.L. OTHER DOCUMENTS AFFECTED 

EUROCOPTER will modify the following documents with respect to this ALERT SERVICE BULLETIN: MET, 

IPC. 

1.M. TOOLING AFFECTED 

Not applicable. 

1.N. INTERCHANGEABILITY OR MIXABILITY OF PARTS 

Not applicable. 
 ALERT SERVICE BULLETIN AS350 

Approved under EASA DOA No. 21J.056. 29.00.13 Page 5/10

 2010.07.26

2. ACCOMPLISHMENT INSTRUCTIONS 

2.A. GENERAL 

Read the general instructions concerning the installation of hoses as per MET Work Card 29.10.10.404 and 

MTC Work Card 20.07.03.408. 

2.B. OPERATIONAL PROCEDURE 

2.B.1. Preliminary steps 

Comply with the general instructions concerning the hydraulic power system as per MET Work Card 

29.00.00.301. 

Open the MGB and engine cowlings. 

2.B.2. Embodiment of modification 074238 (Figures 1 and 2) 

- Remove attachment ties (e) from along both hoses (a) and (b) and recover spreaders (f). 

1) Hose (a): 

- Disconnect hose (a) straight end fitting (c) from the servo-control manifold. 

- Hold hose (a) upwards and plug the straight end fitting. 

- Slide sleeve (1) over hose (a). 

- Remove the plug. 

- Connect hose (a) to the servo-control manifold. 

2) Hose (b): 

- Disconnect hose (b) straight end fitting (d) from the servo-control manifold. 

- Hold hose (b) upwards and plug the straight end fitting. 

- Slide sleeve (2) over hose (b). 

- Remove the plug. 

- Connect hose (b) to the servo-control manifold. 

3) Finishing: 

- Install spreaders (f) and attachment ties (3) as per MTC Work Card 20.02.01.411. 

4) Testing: 

- Disconnect the main rotor pitch-change rods. 

- Move the collective and cyclic controls in all combinations and over their full travel range and make sure 

that the two hoses do not interfere with their environment. 

- Connect the main rotor pitch-change rods. 

2.B.3. Final steps 

Comply with the general instructions concerning the hydraulic power system as per MET Work Card 

29.00.00.301. 
 ALERT SERVICE BULLETIN AS350 

Approved under EASA DOA No. 21J.056. 29.00.13 Page 6/10

 2010.07.26

2.C. IDENTIFICATION 

Record compliance with this ALERT SERVICE BULLETIN Revision 0 in the helicopter documents. 

Record embodiment of modification 074238 in the helicopter documents. 

2.D. OPERATING AND MAINTENANCE INSTRUCTIONS 

2.D.1. Operating instructions 

Not applicable. 

2.D.2. Maintenance instructions 

Pending an update of the maintenance documentation, reinstall the sleeves each time a forward servocontrol hose is installed or replaced. 
 ALERT SERVICE BULLETIN AS350 

Approved under EASA DOA No. 21J.056. 29.00.13 Page 7/10

 2010.07.26

Figure 1 

FWD 

c d

a b
 ALERT SERVICE BULLETIN AS350 

Approved under EASA DOA No. 21J.056. 29.00.13 Page 8/10

 2010.07.26

 

Figure 2: Modification 074238

PRE MOD 074238 

POST MOD 074238 

e

e

f

3 

3

f

2

1 

a

b
 ALERT SERVICE BULLETIN AS350 

Approved under EASA DOA No. 21J.056. 29.00.13 Page 9/10

 2010.07.26

3. MATERIAL INFORMATION 

3.A. MATERIAL: PRICE AND AVAILABILITY 

3.A.1. Cost 

The components listed in paragraph 3.C.1. will be delivered free of charge on the operator's order, within 6 

months following receipt of this ALERT SERVICE BULLETIN, issued on the date indicated at the bottom of 

the page. 

3.A.2. Availability 

The operator will be informed of the industrial delivery lead-time on request by the Sales & Customer 

Relations Department. 

3.B. INFORMATION CONCERNING INDUSTRIAL SUPPORT 

Not applicable. 

3.C. MATERIAL REQUIRED FOR EACH HELICOPTER/ENGINE/COMPONENT 

3.C.1. Kits or components to be ordered for one helicopter or one assembly 

Material P/N Item Qty Key Word

Manufacturer Part Number SAP Part Number 

 

706A34-402-225 706A34402225 1 1 Sleeve

706A34-402-224 706A34402224 2 1 Sleeve

Sleeve 706A34-402-225 is installed on hose 704A34-412-033. 

Sleeve 706A34-402-224 is installed on hose 704A34-412-035. 

3.C.2. Material to be ordered separately 

Material P/N Item Qty Key Word

Manufacturer Part Number SAP Part Number 

E0043-1C0 738943 3 AR Attachment tie

The materials shown by an asterisk "*" or required for compliance with the Tasks and/or Work Cards 

referenced in paragraph 1.K., can be ordered from the INTERTURBINE company: 

Website: http://www.itlogistics.de

Phone: +49.41.91.809.300

AOG: +49.41.91.809.444.
 ALERT SERVICE BULLETIN AS350 

Approved under EASA DOA No. 21J.056. 29.00.13 Page 10/10

 2010.07.26

3.D. PROCUREMENT CONDITIONS 

Order the required quantity (unless otherwise specified) 

from 

EUROCOPTER 

Etablissement de Marignane 

Direction Ventes et Relations Client 

ECR. 

13725 MARIGNANE CEDEX 

FRANCE 

NOTE 1

For ALERT SERVICE BULLETINS, order by: 

Telex: HELICOP 410 969F. 

Fax: +33 (0)4.42.85.99.96. 

NOTE 2

On the purchase order, please specify the mode of transport, 

the destination and the serial numbers of the helicopters to be 

modified. 

4. APPENDIX 

Not applicable. 

 ALERT SERVICE BULLETIN AS350 

Approved under EASA DOA No. 21J.056. 29.00.13 Page 10/10

 2010.07.26

3.D. PROCUREMENT CONDITIONS 

Order the required quantity (unless otherwise specified) 

from 

EUROCOPTER 

Etablissement de Marignane 

Direction Ventes et Relations Client 

ECR. 

13725 MARIGNANE CEDEX 

FRANCE 

NOTE 1

For ALERT SERVICE BULLETINS, order by: 

Telex: HELICOP 410 969F. 

Fax: +33 (0)4.42.85.99.96. 

NOTE 2

On the purchase order, please specify the mode of transport, 

the destination and the serial numbers of the helicopters to be 

modified. 

4. APPENDIX 

Not applicable.